Electron discharge device



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Filed April l5, 1944 @Wm 6 E949. n. M. POWERS ELECTRON DISCHARGE DEVICEwww 2 sheets-sheet 2 Filed April 1s, 1944 Patented Sept. 6, 1949 UNITEDSTATES ETENT OFFICE 2,481,151 ELECTRON DISCHARGE DEVICE Donald M.Powers, Boston, Mass., assignor to Raytheon Manufacturing Company,Newton, Mass., a corporation of Delaware Application April 13, 1944,Serial No. 530,861

15 Claims. (Cl. 250-27.5)

This invention relates to a magnetron oscillaand I0 which project fromthe opposite ends of tor of the plural-anode cavity type which is thecathode structure. One of the conductors 9 adapted to generateoscillations of hyper-fremay be electrically connected `to the cathodequencies having wavelengths of the order of a few sleeve 8, while theother conductor lo is insulated centimeters or less. 5 from said sleeve.The cathode 5, is supported -by In devices of this kind it is desirablethat the a pair of lead-n conductors ll welded respecoscillationsgenerated be fed into a transmission tively to the end conductors 9 andIll. The lead-in system, such as a hollow Wave guide, in a dleCtconductors Il pass through glass seals l2 mounted and efficient manner.It is therefore an object the mitm. of conducting i)mes i9, heimat ofthis invention to couple the energy of the oscil- 10 ically fastenedthrough the Wan o'f the envelope lating portions of such a magnetroninto a hollow 1 adjacent the opper and lower ends thereof.

wave guide in a direct, simple and el'licient man- When such a magnetronis placed between nel" suitable magnetic poles Illv to create alongitudinal Another object of this invention is to devise l5 magneticfield and the device is energized; OSCil the above type 0f Couplmg sothat the tmpedantes lations are set up with the opening between each @tthe Varous parts Qt the System al? ntttchett pair of plates 5 operatingas a. tuned oscillating Wlth eactt other by mlPedance ttutltltmg 0lcavity. These, oscillations are-fed, yby means of a t1" anstomm? meansof ampie. con gutttlqtll construction tov be described below, into ahollow The foegomg and other 0 Jeets of 1s mt'eu' wave guide l5,preferably of a rectangular crosstion will be best understood from thefollowing 3" q 1 ectlon and foirned of a suitable conductingmatedescriptlon of exemphcations thereof, reference rial, Such ascopper. The wave. guide l5 is wrapbeing had to the accompanyingdrawings, wherepedi around the Outside of the envelope i, prefelm m: cably with the long dimension of the cross-seotion mt fln rotlatrgf ireeeirllofdi 1.,-, of said wave guide l 5 in contact with the enternal Fig2; waiglcofuthe elziveloetl. J'GIlhe wavci guidie llis her; I. l me 1 ay so ere o e enve ope wiere 1 iinlfalfaigganisyerse 'Cross Sectmn takenalong comes in contact with said envelope. The wave Fig- 3 is a Vi,EWsimilar to Fig 2 of another em guide l5 is closed at one end t5, and isconnected bodiment of my invention; i( at the other end through a chokecoupler il to Fig [i is a fragmentary Cross sectlon taken an additionalwave guide I8 through which the adong line ,i of Fig. 3; oscillationsmay be led to an external utilization Fig. 5 is a fragmentary transversecross-section uevlce' In Order to Complete the hermetm Seat of anotherembodiment of my invention; and ai glass member l 9 may be Seated-acr9ssthat por Fig. 6 is a fragmentary ci.oss seciion taken is tion of thechole coupler Il which 1s connected along une e-e of Fig. 5. t0 the Wavegulde t5 The magnetron illustrated in Figsl and 2 In order to feed theoscillating energy directly comprises a tubular envelope l made of acylinder into the Wai/e guide l5, a plurality of coupling of Conductingmaterial such as Copper. en@ IOODS are loated in Selected OSC'Hat/ng'CaV" of the envelope are Covered ,by Caps 2 and 3 likeil ties betweenadjacent anode plates 5. One end wise formed of conducting material,such as of each of said coupling loops 2B is imly and copper, andhermetically soldered in place on electrically Connected t0 the innerWoll 0f the the ends of the envelope |.The envelope l is envelope l.Theother end of each of the loops formed with a central annularprojection fs. A 23 S Connected t0 a COIldllCOl 2| Which extendsplurality of radially-disposed plates 5 are soldered 4.5 through anopening 22 in the. side Walls of the in place along the inner sur-faceof the projection enveope l into the interior of the wave guide l5 Theinner ends of the radial plates 5 are where said conductors 2| serve asexciting probes adapted to serve as anodes and receive electrons forsaid wave guide.

emitted from a `centrally-disposed cathode 6, For max mum eiciency theprobes 2l should which is preferably of a thermionic indirectly- 5o feedenergy into the wave guide l5 in the proper heated oxide-coated type.lIhe cathode 6 is prophase relation to the Wave propagated through videdwith an internal heater 'l and an outer consaid wave guide to reinforcethe wave by being ducting sleeve B, preferably coated with the usual inphase agreement therewith. If, for example, thermonically-emitting oxidecoating. The heatthe loops 2i] are located in cavities which oscillateer 'i is provided with a pair of end conductors il 55 in time phase Witheach other, then the probes 2| should bespa-ced apart along the waveguide I5 by a distance mkg 2 Where 11.1 is an even Whole number and xgis the wave length of the radiations within the wave guide I5. If,however, the loops are located in cavities which oscillate 180 out oftime phase with each other, then the probes spaced apart along the waveguide I5 by a distance mkg 2 where m is an odd whole number. The closedend I6 is located the proper distance from the adjacent probe 2|, sothat radiations which are propagated toward said closed end I6 and arereflected therefrom combine with the radiations propagated in theopposite direction in phase agreement therewith so as to produce aresultant propagation of the hyper-frequency energy in a directionthrough the wave guide I5 toward the choke coupler I'I and the externalwave guide I8. Y

extend from predetermined oscillating cavities within the magnetronthrough the walls of the envelope I and into the wave guide I5. Thetapered slots 23 Serve as impedance matching elements so that theimpedance of the oscillating cavities is matched to the impedance of thewave guide. For this purpose the inner end of each slot 23, looking intothe oscillating cavity within the magnetron, is suiciently smaller thanthe outer end of said cavity 23, looking into the wave guide I5, so asto produce the necessary impedance matching.

Instead of matching the impedances through tapered slots, as describedin connection with Figs. 3 and 4, impedance transforming slots 24', asillustrated in Figs. 5 and 6, may be utilized. Each slot 24 is providedwith a section 25 of increased length, looking into the oscillatingcavity, and connected with a section 26 of decreased length, lookinginto the wave guide I5. The shoulder 2'! between the sections and 2Sintroduces an impedance transforming discontinuity which together withthe sections 25 and 26 results in the desired impedance matching.

It is desirable that the standing wave ratio adjacent the choke couplerbe as low as possible in order that a maximum of energy be propagatedthrough the wave guide section I8. This ratio in the embodimentdescribed above may be reduced by causing the amount of power fed intothe wave guide section I5 to increase progressively as the choke couplerI'I is approached. This may be done in Figs. l and 2 by adjusting thelength of the probes 2S to be progressively greater. Likewise inFigs..3-6, the coupling slots may be ad justed to be progressivelylarger. Also the standing wave ratio can be reduced by dissipating someof. the energy at the closed end I6 of the wave guide section I5, as bycoating the inside surface of said end I6 with a resistance material.Also a slight deviation of the probes of Figs. 1-2 and 2I should be CTIthe slots of Figs. 3-6 from that as described above Will tend to reducesaid standing wave ratio.

Of course it is to be understood that this invention is not limited tothe particular details as described above as many equivalents willsuggest themselves to those skilled in the art.

What is claimed is:

1. A high frequency oscillator comprising an electron discharge tubehaving a plurality of electromagnetically coupled cavity resonatorstherein, and a hollow wave guide adapted to be excited by said cavityresonators, a plurality of said cavity resonators being directly coupledto said wave guide-said wave guide having a closed end and an oppositeend section through which end section the oscillatory energy is led outof the oscillator.

2. A high frequency oscillator comprising an electron discharge tubehaving a plurality of cavity resonators therein, and a hollow wave guideadapted to be excited by said cavity resonators, a plurality of saidcavity resonators being directly coupled to said wave guide at aplurality of points spaced along said wave guide, said wave guide havinga closed end and an opposite end section through which end section theoscillatory energy is led out of the oscillator.

3. A high frequency oscillator comprising an electron discharge tubehaving a plurality of cavity resonators therein, and a hollow wave guideadapted to be excited by said cavity resonators, each of said cavityresonators being directly coupled to said wave guide through animpedance matching slot, said slot having predetermined cross-sectionaldimensions looking into said cavity resonator and diierentcross-sectional dimensions looking into said wave guide, whereby theimpedance of said cavity resonator is matched to the impedance of saidwave guide.

4. A high frequency oscillator comprising an electron discharge tubehaving a plurality of cavity resonators therein, and a hollow wave guideadapted to be excited by said cavity reso nator, each of said cavityresonators being directly coupled to said wave guide through animpedance matching tapered slot, said slot having predeterminedcross-sectional dimensions looking into said cavity resonator anddiierent cross-sectional dimensions looking into said wave guide,whereby the impedance of said cavity resonator is matched to theimpedance of said wave guide.

5. A high frequency oscillator comprising an electron discharge tubehaving a plurality of cavity resonators therein, and a hollow wave guideadapted to be excited by said cavity resonators, each of said cavityresonators being directly coupled to said wave guide through animpedance transforming slot, said slot having substantially uniformpredetermined cross-sectional dimensions looking into said cavityresonator and extending through said slot for a predetermined distanceand different substantially uniform predetermined cross-sectionaldimensions looking into said wave guide and extending the runningdistance through said slot, whereby an impedance transformingdiscontinuity is produced within said slot.

6. An electron discharge device comprising a cathode, an anode, saidanode having a plurality of electron-receiving portions disposed aroundsaid cathode, and a plurality of grooved portions spaced from said firstportions and likewise disposed around said cathode, said groovedportions constituting cavity resonators, a hollow wave guide wrappedaround said anode, a plurality of guide wrapped said cavity resonatorsbeing directly coupled to said wave guide, said wave guide having an endsection through which the oscillatory energy is led out of theoscillator.

7. An electron discharge device comprising a cathode, an anode, saidanode having a plurality of electron-receiving portions disposed aroundsaid cathode, and a plurality of grooved portions spaced from said rstportions and likewise disposed around said cathode, said groovedportions constituting cavity resonators, a hollow wave around saidanode, a plurality of said cavity resonators being directly coupled tosaid wave guide, said wave guide having a closed end and an opposite endsection through which end section the oscillatory energy is led out ofthe oscillator.

8. An electron discharge device comprising a cathode, an anode, saidanode having a plurality of electron-receiving portions disposed aroundsaid cathode, and a plurality of grooved portions spaced from said rstportions and likewise disposed around said cathode, said groovedportions constituting cavity resonators, a hollow wave guide wrappedaround said anode, a plurality of said cavity resonators being directlycoupled to said wave guide at a plurality of points spaced along saidwave guide, said wave guide having an end section through which theoscillatory energy is led out of the oscillator.

9, An electron discharge device comprising a cathode, an anode, saidanode having a plurality of electron-receiving portions disposed aroundsaid cathode, and a plurality of grooved portions spaced from said rstportions and likewise disposed around said cathode, said groove portionsconstituting cavity resonators, a hollow wave guide wrapped around saidanode, a plurality of said cavity resonators being directly coupled tosaid wave guide at a plurality of points spaced along said wave guide,said wave guide having a closed end and an opposite end section throughwhich end section the oscillatory energy is led out of the oscillator.

10. A magnetron comprising a cathode, an anode, said anode having aplurality of electronreceiving portions disposed around said cathode,and a plurality of grooved portions spaced from said rst portions andlikewise disposed around said cathode, said grooved portionsconstituting cavity resonators means adjacent said cathode for producinga magnetic field transverse to the discharge path between said cathodeand said electron-receiving portions, a hollow wave guide wrapped aroundsaid anode, a plurality of said cavity resonators being directly coupledto said wave guide. said wave guide having an end section through whichthe oscillatory energy is led out of the oscillator.

11. A magnetron comprising a cathode, an anode. said anode having aplurality of electronreceiving portions disposed around said cathode,and a plurality of grooved portions spaced from said rst portions andlikewise disposed around said cathode, said grooved portionsconstituting cavity resonators, means adjacent said cathode forproducing a magnetic eld transverse to the discharge path between saidcathode and said electron-receiving portions, a hollow wave guidewrapped around said anode, a plurality of said cavity resonators beingdirectly coupled to said wave guide at a plurality of points spacedalong said wave guide, said wave guide having a closed end and anopposite end section through which end section the oscillatory energy isled out of the oscillator.

12. A high frequency oscillator comprising an electron discharge tubehaving a plurality of cavity resonators therein, a hollow Wave guideadapted to be excited by said cavity resonators, a plurality of saidcavity resonators being directly coupled to said Wave guide at aplurality of points spaced along said wave guide, said wave guide havinga closed end and an opposite end section through which end section theoscillatory energy is led out of the oscillator, and energy dissipatingmeans at said closed end.

13. A high frequency oscillator comprising an electron discharge tubehaving a plurality of cavity resonators therein, a hollow wave guideadapted to be excited by said cavity resonators, a plurality of saidcavity resonators being directly coupled to said wave guide at aplurality of points spaced along said wave guide, said wave guide havinga closed end and an opposite end section through which end section theoscillatory energy is led out of the oscillator, and means at saidcoupling points for progressively increasing the energy fed into saidWave guide from said cavity resonators as said opposite end section isapproached.

14. A high frequency oscillator comprising an electron discharge tubehaving a plurality of cavity resonators therein, and a hollow wave guideadapted to be excited by said cavity resonators, each of a plurality ofsaid cavity resonators being directly coupled to said wave guide by aprobe at a plurality of points spaced along said Wave guide, said waveguide having a closed end and an opposite end section through which endsection the oscillatory energy is led out of the oscillator, said probesbeing progressively longer as said opposite end section is approached.

15. A high frequency oscillator comprising an electron discharge tubehaving a plurality of cavity resonators therein, and a hollow wave guideadapted to be excited by said cavity resonators, each of a plurality ofsaid cavity resonators being directly coupled to said Wave guide by acoupling slot at a plurality of points spaced along said wave guide,said wave guide having a closed end and an opposite end section throughwhich end section the oscillatory energy is led out of the oscillator,said coupling slots being progressively larger as said opposite endsection is approached.

DONALD M. POWERS.

REFERENCES CITED The following references arefof record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,084,867 Prinz et al. June 22,1937 2.088.749 King Aug. 3, 1937 2,108,900 Peterson Feb. 22, 19382,147,717 Shelkunoi'f Feb. 21, 1939 2,151,157 Shelkunoi Mar. 21, 19392,153,728 Southworth Apr. 11, 1939 2,154,758 Dallenbach Apr. 18, 19392,190,668 Llewellyn Feb. 20, 1940 2,247,077 Blewett et al. June 24, 19412,284,405 McArthur May 26, 1942 2,411,151 Fisk Nov. 19, 1946 2,411,953Brown Dec, 3, 1946 2,421,912 Spooner June 10, 1947

